AB0339 DYNAMIC RESPONSE TO INTRAVENOUS IRON, MEASURED BY NOVEL RETICULOCYTE INDICES, AS A PREDICTOR OF COEXISTING IRON DEFICIENCY IN ANAEMIA OF INFLAMMATION
Authors: P. Singh, V. Ingle, R. Joshi, D. Joshi, A. Kotnis
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Anemia of inflammation (AI) can be referred to as the proverbial "Starvation amidst plenty" as body iron stores are unavailable for the erythron[1]. Anemia of iron deficiency(AID) is prevalent in developing countries and often coexists with AI [2]. There is no simple, single static iron or red blood cell parameter, which reliably predicts iron deficiency in patients with AI. The erythron is in a state of flux; modulated by physiological demands (e.g., hemoglobin(Hb) levels, tissue hypoxia), metabolic substrates (e.g., iron, Vitamin B12, Folic acid, etc), and pathologic states (e.g., inflammation, malignancies, etc). Therefore, even at the risk of oversimplification, it may be hypothesized that dynamic tests are needed to determine limiting factors for erythron responsiveness. <h3>Objectives</h3> This study aimed to evaluate the performance of novel reticulocyte (Ret) indices Reticulocyte Hemoglobin (RetHb) and Immature Reticulocyte Fraction (IRF) in identifying coexistent iron-deficient states in AI. We correlated the change in RetHb &amp; IRF with an increase in Hb after intravenous iron in AI. <h3>Methods</h3> In this study, we have used intravenous iron in patients with AI (hemoglobin&lt;10gm/dL and serum ferritin &lt;500ng/ml) and employed changes in Ret parameters - RetHb/IRF to predict coexisting iron deficiency "Iron challenge test". All participants received intravenous Iron sucrose after sensitivity testing (100 mg day 1 and 400mg Day 3). An increase in Hb of at least 1gm/dL at one month was considered a positive iron response &amp; diagnostic of coexistent iron deficiency with AI. Change in RetHb/IRF on 3rd day from baseline was compared in Iron responders(AID with AI) vs non-responders (AI only). <h3>Results</h3> Out of 62 patients who were enrolled, 46 patients completed the study protocol &amp; were finally analyzed for the study. The majority of the participants had chronic autoimmune inflammatory disorders (Rheumatoid arthritis-30 Ankylosing Spondylitis-5, Systemic Lupus Erythematosus-4, Sjogren -1, Psoriatic arthritis-1) while the rest were Chronic liver disease/Chronic heart disease. About 63% of participants were iron responders and therefore, considered to have AID with AI; while the rest were iron non-responders and considered to have predominant AI. There was no significant difference between the change in RetHb/IRF amongst responders and non-responders at 72 hrs (Table 1). Baseline serum iron parameters (Serum iron, Total Iron Binding Capacity, % Saturation, Serum ferritin) and Red blood cell (RBC) indices (Mean corpuscular volume, Mean Corpuscular Hb) were also not statistically different in iron responders vs non-responders. <h3>Conclusion</h3> Diagnosing and treating coexisting iron deficiency in AI is a clinical conundrum. In this study, a significant proportion of AI (37%) didn't respond to intravenous iron at 1 month. Baseline iron parameters like serum ferritin/ % saturation and RBC Mean corpuscular volume didn't predict response to iron in this study. Change in novel automated Ret indices (RetHb and IRF) failed to predict response to iron and therefore, failed to diagnose co-existent iron deficiency in AI. Dynamic studies demonstrating erythron responsiveness to iron therapy using "point of care" automated hematologic parameters may provide a template for further studies. <h3>Reference</h3> [1] Guenter Weiss, Tomas Ganz, Lawrence T. Goodnough; Anemia of inflammation. Blood 2019; 133 (1): 40–50. 2. Shaw JG, Friedman JF. Iron deficiency anemia: focus on infectious diseases in lesser developed countries. Anemia 2011;260380 <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> None Declared.